Data review offers new insights into Alemtuzumab

June 15, 2017

A new review of phase III trial datasets of Alemtuzumab helps explain the drug’s effects and side effects. Researchers say this new information will help contribute to the effective management of people with MS, firstly during the decision-making process about disease-modifying treatment, and secondly in people who have been treated with Alemtuzumab, to ensure the risks associated with dangerous side effects are minimised.

Alemtuzumab is a highly effective drug for multiple sclerosis. However, there is an almost 50 percent risk of secondary autoimmune diseases, some of which are life-threatening, such as platelet and kidney diseases. Although knowledge about these adverse effects was included in conference presentations and licensing submissions to European and U.S. regulators, critical data to explain secondary autoimmune disease had not been scrutinised and published following peer review.

Through a Freedom of Information request to the European Medicines Agency, researchers from Queen Mary University of London gained access to the phase III trial datasets of Alemtuzumab. Their analysis and interpretation provides new insights into the drastic responses of the immune system in people with MS taking Alemtuzumab.

The researchers discovered a massive and rapid re-population of a subset of B cells in the absence of effective T cell regulation, which they say helps create an environment for secondary autoimmune disease. This also allows a marked antidrug response that can become problematic in some people taking the drug. According to the researchers, controlling this B cell subset "overshoot" after Alemtuzumab administration until T cell regulation recovers, may limit the risk of secondary autoimmune disease and make it an even better medicine.

While they saw a long-term suppression of T cells, believed by many to be the cause of the problem, they also saw loss of memory B cells, which they say offers a new explanation on why Alemtuzumab is effective in people with MS. Indeed it may provide insight of how all other drugs work in MS and ties aspects of the potential cause and treatments together.